Device for controlling internal combustion engine drive



26, 5 H. J. M. F'ciRs-rER 2,713,800

DEVICE FOR CONTROLLING INTERNAL COMBUSTION ENGINE DRIVE Filed Oct. 51950 3 Sheets-Sheet l TAIL/613,701! $49: 54575: 4 MW v G July 26, 1955H. J. M. F'cSRsTER DEVICE FOR CQNTROLLING INTERNAL COMBUSTION ENGINEDRIVE Filed Oct. 5, 1950 3 Sheets-Sheet 2 Ml-CLLM QM July 26, 1955 I vH. J. M. FbRSTER 2,713,800

DEVICE FOR CONTROLLING INTERNAL COMBUSTION ENGINE DRIVE Filed Oct. 3,1950 3 Sheets-Sheet 3 m m 1 121 I29 131i 3 111' 115 11 1 111 I56 117 I3015/ I]! If! 7.13 133 1.71

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United States Patent DEVICE FfiR ONTRQLLING INTERNAL COlVIBUSTIONENGINEBRIVE Hans J. M. Forster, Harthausen A. F., Kr. Esslingen(Neckar),.Germany, assignor to Daimier-Benz Aktiengesellschaft,Stuttgart-Unterturkheim, Germany AppiicationOctoberS, 1950, Serial No.188,198 Claims priority, appiication Germany Qctober 5, 1949 17 Claims.((11. 74-472) efiicient, and especially suitable control mechanism forthe operation of the machine, particularly a motor vehicle, primarily ina manner enabling the driver to obtain an accurately predeterminedcontrol of the output of the power plant'by adjusting a single device.

The invention provides more particularly a control which renders theshifting of gears or changing of the gear ratio dependent upon the speedof the driven shaft of the transmission, that is, dependent upon roadspeed, with a simultaneous control by throttling the power output of theengine.

An important object of the invention is to combine differentpossibilitiesof control and to simplify and im prove the automaticshift, in such a manner that for each respective shift level, adjustableat the will of the driver, maximum power output of the engine isutilized and peak efficiency of operation is obtained simultaneouslytherewith.

Accordingly, an essential feature of the invention consists incontrolling the drive so that, at least within the range of several ofthe upper gear positions or ratios, the power output of the engine, atall speeds of the driven shaft, that -is, at all road speeds, isessentially constant, assumes only a slightly inclined, for example,alternately rising and falling course within relatively small powerlimits, with the power output level being adjustable at willorpreselectable.

A further object of the invention resides in the provision of a controlsystem for drives of thedescribed character wherein the element whichaffects the engine power is controlled by one or more factorsdetermining the power of the engine (for example, engine speed, chargeor the like), and wherein the associated gear shifting assembly is notonly shifted dependent upon the driving speed, engine speed, oranothercorresponding value, but also dependent upon the existing or selectedpower output of the engine, the pressure at the narrowest point of thecarburetor Venturi tube, or of a Pitot tube or the like being employedas an especially suitable measure of function of the engine power to beused in controlling the latter.

Another object of the invention resides in the provision of anarrangement in which, with increasing speed of the driven shaft of thetransmission, the prime mover is operated, within each of the severalgear conditions, alternately first unthrottled or essentiallyunthrottled and then with gradually increased throttling up to the shiftto the next higher gear, so that for each gear condition a certaininitial increase in power occurs corresponding to the power curve, andthen a decrease in power takes place in turn prior to the shift to thenext higher gear condition or ratio.

2,713,800 Patented July 25, 1955 A further object of the inventionresides inproviding a control arrangement for obtaining uniform poweroutput of the engine at a preselected power level, without specialreaction on the part of the operator to accommodate himself to theresistance or load on the driven shaft of the machine by utilizing thepressure below atmospheric at the narrowest point of the carburetorVenturi tube as an engine control factor which changes, within the rangeconsidered to be suitable for operation of the vehicle, nearlyproportional to the power output of the engine, with a minor drop withincreasing engine speed.

A further objectof the invention is to provide control mechanism which,when applied to automatically shifting transmissions, efiects the shiftfrom one gear .to another gear automatically at predetermined throttleposition of the engine, without substantial drop of power from theadjusted or selected power level during the interval of the shift andlikewise .during operation .within an engaged gear position and theacceleration of the vehicle takes a steady course and the ,shift of thetransmission from lower to higher gears is accomplished practicallyimperceptibly for the driver and occupants of the car while the demandedpower of the engine is fully utilized and peak efficiency of operationis obtained, and wherein the control mechanism effects automaticadjustments of the drive in response to changing road resistance, forexample, in hilly teritory, in an especially advantageous manner, sothat, decreasing road speed, corresponding to increasing roadresistance, results ina certain power increase at the same time.

Still another object is to provide control mechanism having the abovecharacteristics and adapting the selection of the gears to the totalroad resistance, so that-it is possible for the machine to run-at leastundernormal circumstances--in nearly unthrottled condition, as soon asthe vehicle has reached its maximum speed, 'determined by the roadresistance, in high gear (for example, overdrive) and this maybe so evenif the operating member which adjusts the power level is adjusted topart-load only. 7

Still another object is to provide control mechanism having the abovecharacteristics and which when the preselected powerlevel is suddenlyincreased, effects a return shift to the next lower gear ratio, and when'the power level'is suddenly decreased, then a shift to the'next highergear takes place, in the first case provision may be made for a suitableperceptible resistance, and in the second case for a suitable retardingdevice.

A still further object is to prevent the engine noise from surpassingthe road noise in the lower gear'sta'ges, provision beingmade in thelatter for a premature shift to the next higher gear deviating from thepreviously described control, and furthermore, the return shift fromhigher to lower gear may suitably take place at a lower speed of thedriven shaft than that at which the up-shift takes place.

Finally, another'objectis to provide for the employment of the engine asa brake in the control as embodied in the invention.

In accordance with the present invention, the above objects areaccomplished by providing a control device which comprises an outputregulator by means of which output regulator and automatic shiftgearare, for example, linked to a mutual operating member (for 'example, afoot pedal) which can be adjusted by the driver, while regulation of thepower output is accomplished, for example, by means of an adjustablefeeler mechanism such as a diaphragm case responsive to the pressurebelow atmospheric in the carburetor venturi throat and subject tooverriding control by the operator to adjust the power level. Thisfeeler in turn adjusts a sliding control valve for an auxiliary forcewhich controls the power output of the machine. This auxiliary forceactuates, for example, depending upon the position of the control valve,a piston or the like which opens or closes the output regulator of theprime mover (for example, a throttle valve in the air intake of theengine).

The above and other objects, features and advantages of the presentinvention will be apparent in the a following description ofillustrative embodiments thereof, which description is to be read inconnection with the accompanying drawings, and the invention consists inthe mode of operation, combinations of elements and details ofconstruction appearing in the description and drawings and defined inthe appended claims.

In the drawings: Fig. 1 is a shift diagram of a known automatic shiftcontrol,

Fig. 2 is a shift diagram for an automatic shift control embodying thepresent invention,

Fig. 3 is a schematic layout illustrating a power output regulation andshift control embodying the features of the invention.

Fig. 4 is a schematic layout showing the details of a shift deviceincluded in the embodiment of the invention illustrated by Fig. 3, and

Fig. 5 is a schematic layout similar to that shown in Fig. 3, butapplied to an arrangement for using the engine as braking power.

In the diagrams, Fig. l and Fig. 2, the-loads on the engine for fivedifferent gear ratios of an associated transmission are plotted againstthe road speed v. The fully drawn out curves I to V are the power outputcurves at unthrottled operation of the engine (that is, with fullyopenthrottle in case of a carburetor engine). The fifth speed or gear ratiois used as overdrive or overgear. The total resistance of the vehiclecomposed primarily of road resistance and air resistance is represented,by way of example for normal conditions on level roads, by the curve W.

Fig. 1 shows a hitherto usual mode of shift control for an automaticgear shift. The shift is accomplished in response to certain road speedsat fully-open throttle and normal operating position, for example, fromfirst to .1

second gear at a road speed of via, from second to third gear at v23,from third to fourth gear at 1 34. and from fourth to fifth gear at1/45. The power will, with rising road speed, at first rise on the poweroutput curve I for the first gear ratio up to point b1, at which theautomatic shift to second gear takes place. Then the power suddenlydrops down to value (12, and hereuponlikewise at open throttleascends011 the power output curve II for the second gear ratio up to point b2,whereupon the shift to point as for the third gear takes place at roadspeed we. The further power course is in corresponding mannerrepresented by the serrated curve a3b3a4b4a5bw The point bw representsthe point of equilibrium between full throttle power output of engine inoverdrive and total resistance corresponding to curve W.

If the vehicle, instead of being driven with wide-open throttle, isdriven under lesser power demand, that is, with partially-open throttleonly, then the power delivered during acceleration from standstill up toa point of equilibrium has correspondingly lowered values, for example,by the points on the dotted curves I0, Ho etc., which define theserrated curve Obo1-ao2boz etc.

By shifting into low operating position the road speeds at which theshift from one gear ratio to the next takes place at the lower gears can(in the known modes of shifting) be transferred to higher values, by wayof example for the shift from first to second gear to the higher valuewe, and for the shift from second to third gear to the higher value v23.The course of power at open throttle is in this case represented by theserrated curve Ob1-a2-b2-a3. A further shift to higher gear speeds isgenerally not provided for within this range of operation.

The shift method or pattern described in connection with Fig. 1 has thedisadvantage that a sharp power drop takes place at every shift, whichresults in a correspondingly unsteady acceleration curve for the vehicleand likewise in lower efficiency.

According to another one of the hitherto proposed modes of shiftcontrol, the shift takes place at the precise moment or speed at whichthe power curve for the respective gear position or gear ratio andrespective throttle position, intersects the full-load or full throttlecurve for the immediately following gear position, that is, by way ofexample, at partially-open throttle, at the intersection point of thecurve In with curve II. However, since the throttle is only partiallyopened, in this case a corresponding power drop also takes place fromthe power on curve 10, at the point of intersection with the curve II tothe power on curve H0 at the same road speed as said point ofintersection, provided that the operator does not happen to operate thevehicle with wide-open throttle at the precise moment at which the shiftis made.

As distinguished from the hereinbefore described systems, Fig. 2represents a method of shift control, proposed in accordance with theinvention. The driver preselects by way of example any desired powerlevel for the engine, for example, a power output level N, N or N". Theoutput control of the engine is so adjusted that the engine runs withwide-open throttle as long as a further regulation impulse will not begiven. When the machine is put in operation and the power level N hasbeen set by the driver, then the power output of the engine rises withincreasing road speed and at wide-open throttle up to point B1corresponding to the speed v1 on the curve I. At this point a feelermechanism, which has been set to value N by the driver, begins to act,in response to further increasing road or engine speed, on the throttlevalve of the engine to adjust the latter towards its closed position. Ifan accurate and acutely responsive feeler mechanism is available, thenit is possible to achieve the closing of the throttle valve in each caseonly so far that the power level N remains constant through the wholerange of shift control, hence, the power curve would run exactlyhorizontal from point B up to point B2 on curve II at which point theshift from first to second gear takes place and the throttle valve atthe time of such shift is restored to wideopen position. The course ofpower would then occur on the horizontal line N from E2 via B3, B4, B5etc. up to the intersection point of horizontal line N and curve W, sothat the shift control is effective to change the gear ratios withoutany loss of power from the selected power output level.

However, in practice it will usually be more suitable to use a feelermechanism acting in a slightly different mannor. in the embodimentaccording to Fig. 3, the pressure below atmospheric or vacuum at thethroat of the carburetor venturi is used as the power-dependent value.

Within the control range to be considered this pressure belowatmospheric is sufiiciently proportional to the power output of theengine to make it useful for the desired method of controi. Numeral l inFig. 3 represents the control member which is manipulated by theoperator, and which is connected to a linkage 2 for reciprocating thelatter to control, by means of a lever 3, a feeler mechanism. The feelermechanism includes a diaphragm case or ancroid 4, connected to the lever3 and to a control valve 5. The linkage 2 is also connected,

'15 or through a line 16 to the topside 17 of the piston 15, dependingupon the position ofthe valve 5. The side of the piston 15 which at anytime is not supplied with oil is communicated through either line 13 orline 16 past the control valve 5 with the chambers 18 and 19respectively, which open to atmospheric pressure. The throttle plate 29in the air intake 21 of the engine is operated by the piston 15. Besidesshift lever 1 the road speed of the vehicle also acts uponthe automaticshiftgear 7, for example, by way of a mechanical or hydraulic linkage22, in such a manner that an adjustment of the lever 1 toward the leftand an increase in road speed oppositely affect the automatic shiftgear7. Then, dependent upon the magnitudes of the opposite effects of themanipulation of control lever 1 and of the road speed, the shift fromone gear ratio to another takes place as indicated schematically at 23.The shift, for example, can be effected by a control valve (seen in Fig.4) which, under the effect of a spring which is to be drawn taut by thelever 1 and under the effect of a pressure of a fluid which changes withthe road speed, adjusts itself to a respective position of equilibrium.A similar effect is, for example, obtainable through a compensatinglever, not shown, to whose three points of application are connectedlever 6, linkage 1:2 and control member 23 which eifects the shift ofthe gears.

Further, provision may be made for a lever 24 or the like, asschematically indicated, which, as the foot lever 1 is released,positively closes the throttle 2G in order to provide a positive controlwithin the range of pressures of less than atmospheric. in such a case aspring loaded device 25 can be interposed in the linkage which connectsthe piston 15 with the throttle plate. A manually adjustable lever witha spring loaded stop 26 may serve for limiting the travel of theoperating lever 1. The stop can be adjusted by the operator, beforestarting or while driving, to a position defining an upper power limitwhich appears to be suitable to him. The operators foot may then rest onthe lever 1 to move the latter against the Spring loaded stop and thedriver is induced to attain economical fuel consumption, because he canonly change to higher power and eventually less economical fuelconsumption by overcoming the spring resistance of the stop. The mode ofaction of the described device is as follows:

In Fig. 3 the no-load position of lever 1 is indicated at x0, thefull-load position x1 and the position for the engine brake as. Thelever being in an intermediate position x, for example, corresponding tothe adjusted power level N of Fig. 2. When the vehicle is just being setin motion from a standstill, the control housing 8 is still underatmospheric pressure, and the aneroid 4 is contracted to raise thecontrol valve 5 to its highest position corresponding to position x ofthe lever 1. Even during this initial movement of the vehicle, the line12 is supplied with fluid under pressure and the same flows through theopen line 13 into the chamber 14 below the piston 15 and builds up apressure whereby the piston 15 is moved upwardly into the position shownon the drawing and the throttle valve 2i -being released by the lever24is moved into wide-open position. With increasing road and enginespeed the pressure below atmospheric at the narrowest point it) of thecarburetor venturi decreases, that is, the vacuum becomes greater, andthis pressure decrease is communicated to the chamber 8. The aneroid 4expands to move the control valve 5 downwards. However, initial downwardmovement of the 6 valve ,5 does not cause any change in the flow throughthe lines 13 and 16 and the throttle valve is not yet affected.Consequently, the power output ascends from point along the curve I(Fig. 2).

When the road speed v1 is attained, the pressure below atmospheric atpoint 16, and hence in the housing .8, is down to a value and thecontrol valve has executed a certain downward stroke of predeterminedlength, line 13 will be closed by the control valve 5 and line 16connected with the control chamber 11 instead. At this instant, thepiston 15 begins to move downward and to close the throttle valve 20. Asa necessary result of this closing of the valve 20,.the power output ofthe machine will be decreased and the pressure below atmospheric .1 atpoint and in the housing 8 will undergo a proportional increase or risetoward atmospheric pressure. 7 Consequently, the aneroid 4 is contractedand in turn moves the control valve 5 up. A pressure is again built upin the chamber .14 and the throttle is opened. Due to this alternate upand down movement of the control valve 5, the piston willbe adjusted toan intermediate point of equilibrium, which is dependent upon thepressure below atmospheric at point 10, so that the piston 15, withincreasing engine speed and, therefore, at the same gear ratio withincreasing road speed, is gradually moved downwards and the throttlevalve is adjusted towardsits closed position to maintain substantiallyconstant power output even as the road speed increases above v1. Thissubstantially constant power is characterized bythe curve portion Bi-Bs.Since the proportional relationship of the characteristics of thepressure below atmospheric at point 10 to the power varies slightly withincreasing engine speed, the power is decreased by a certain amount, sothat at point A2 it lies somewhat below the adjusted power level N. Atpoint A2, that is, at a road speed via, the power curvell for the secondgear, as applied to wideopen throttle, is reached. The automatic,hereinafter described in detail, is so adjusted that in this instant,that is, at a road .speed we, the shift fromfirstto second gear is made.Due to the shift the speed of the engine is reduced, the pressure belowatmospheric at point 10 decreases, that is, rises toward atmosphericpressure, and the aneroid 4 is again contracted. A pressure is againbuilt up by the oil in the chamber 14 and moves the throttle plate intowide-open position. At a further increase in road speed the power outputrises again from A2 to B2 where the same occurrence as described forpoint B1 is repeated. At a road speed 1223, the shift to third geartakes place at A3, at point A4 to fourth gear, and at point As to fifthgear, resulting collectively in an only slightly wavy or irregularcourse of power from Br via A2, B2, A2, B2, A4, B4,, A5, B5, up to pointAw. At point A power output and total resistance of the vehicle inmotion are in equilibrium: and the maximum speed vw possible with thepower level N is attained.

With a preselected power level, increasing road resistance, for example,when negotiating a hill, moves point Aw towards point B5, and thethrottle opens gradually and the power output of the engine increasessomewhat to compensate for the increased resistance. This corresponds toa certain ability of accommodation of the engine to adjust itself tochanging road conditions. The drivers work is, therefore, substantiallyreduced, since he is less often compelled to react against the changingroad resistance.

As the road resistance continues to increase, the engine at firstcontinues to run with engaged overdrive at wideopen throttle and then ata certain road speed or speed of the driven shaft, the transmission isreturned to the fourth speed or gear ratio. This speed v54 preferablylies lower than the speed v at which the corresponding shift from fourthto fifth gear has taken place, in order to retain the hysteresis effectrequisite for the stability of the control. At the instant of the shiftthe power output would then increase from point =E5-on curve V to F onthe line connecting B4 and A5. However, the return shift, if necessary,may take place on another curve, for example, a return shift from fourthgear to third gear, at a road speed v43, may take place from E4 to F3.

When the lever 1 is adjusted to position x to provide a higher powerlevel, for example, N, then the occurrences which lead to the automaticshift of the transmission are basically the same as those in thepreviously described instance. Since, when the lover I is moved toposition x, the aneroid 4 and therewith the sliding control valve 5 areraised higher, a higher pressure below atmospheric at point 16 is alsorequisite in order to enable the control valve 5 to effect a change inthe flow of oil from line 13 to line 16 and thus bring about a closingof the throttle. Using power level adjustment N this change in the oilflow is reached at point 31. By the adjustment of the lever 1 toposition x, the automatic shiftgear is also affected, so that the roadspeed must rise to higher values, before the successive shifts to thenext higher gear takes place.

If the gear shifts for the power level N are similar to those in thepreviously described case (N), then the second gear would be engagedonly at point A2. Hence, the engine would run at first up to point Bywith wideopen throttle and from point B1 up to point B2 with graduallyclosing throttle. This would, however, under certain circumstances havethe effect that the engine speed becomes so high that the engine noisedrowns the road noise, thereby giving the occupants of the car theimpression that too low a gear is engaged. In order to avoid thisimpression, the road speed at which the first shift takes place can, ifdesired, be lowered, for example, to value V12. In that event the shifttakes place at point C1, at which the wide-open throttle curve II forthe second gear is not yet reached. Consequently, the power drops topoint Dz immediately after the shift. At the same time the speed of theengine is lowered, the pressure below atmospheric at point 10 reducedand the throttle plate again moved into wide-open position. Withincreasing road speed the power rises along curve II from point D2 topoint B2, at which latter point the adjusted power level N is reachedagain. The course of power from first to fifth gear or overdrive istherefore given by the curve B1'-Cr -D: -B2'A3'B3'A4'B4' As'-B5 A\v-'.At point Aw, with slightly throttled overdrive, the maximum speedattainable with the power level N is again reached.

In case of adjustment to a still higher power level, for example, N, itis under certain circumstances desirable to locate the shift speed 1 12for the shift from first to second gear at so low a value that the shifttakes place dircctiy from unthrottled first gear, for example, at pointB1" on curve I, while the shift from second to third gear takes place ata road speed v23" which is short of the curve III, that is, at pointC2". The course of power for the adjusted power level N" is in this casegiven collectively by the following curve: B1-D2"B2"C2-D3"-B3"-A4"B4"Aw".

The control of the power output can, if desired, be arranged in such amanner that, even with the selected low power level (for example, N) theshift from first to second gear takes place at wide-open throttleposition that is, at a point on curve i, or at an intermediate shiftpoint be tween the points B1 and A2, so that an up-shift at throttledengine then occurs for all settings of the power level only in shiftingbetween the higher gear speeds.

When, for example, the selected power output is adjusted to value N andthe engine is in an operational stage corresponding to point B3 (hence,in third gear), a sudden increase of the power level (at essentiallyconstant road speed), effected by movement of the lever 1 from positionx to position x1 which corresponds to power level N, will produce areturn of the transmission to second speed and at a still furtherincrease of the power level, for example, to power level l will producea further return controller L.

to first gear. The return shift, if desired, can be made mechanicallyperceptible depending on the adjustment of the spring stop 26 so thatthe adjustment of lever 1 to a higher power level may be effected onlyagainst the resistance of the stop.

if the selected power output is suddenly decreased (for example, out ofpoint B3) the next higher (hence, for example, fourth gear) would beengaged, as soon as the curve IV (at a point located perpendicularlybelow B3) is undercut. However, a device is preferably provided in thegear shifting device hereinafter described to accomplish such an upshifting only after a certain time lag.

In order to also provide for the use of the engine as a brake in theautomatic operation of the transmission, a special brake position x2 maybe provided for the lever i and is situated beyond the normal zero orneutral position .m. in this brake position, the side 17 of the pistonis steadily supplied with oil under pressure through the steadily openline 16 so that the throttle valve 20 is maintained continuously inclosed position. Another mechanical point of resistance (not shown), forexample, resilient stop similar to the stop 26, may be provided atposition x0 of the lever 1 so that the backward motion to position x2 isperceptible to the driver. Further, the backward motion of the lever toposition x2 may be indicated by a signal, for example, a red lamp. Thebackward motion to position x2 may also be accomplished by means of aspecial, for example, manually adjustable lever (not shown) which isseparate from, or in addition to, the lever 1.

Fig. 4 shows a schematic layout of a preferred automatic gear shiftingdevice embodying the present invention and represented generally by thenumeral 7 in Fig. 3. The output control member 191, corresponding to theiever 1 of 3, is connected to an output control device (not shown),which may be identical with the device shown in Fig. 3 and is omittedfrom Fig. 4 for the sake of clarity. A link M2, connected to the controllever 161, acts upon a controller L consisting of a piston 1d and apilot valve N5 coupled to the latter by means of a spring it'l whichoperates to control the pressure of a control fluid in accordance withthe position of lever 161.

Oil pressure is built up by a single pump 1M which is continuously inoperation or may be replaced by two pumps, one of which may be drivencontinuously by the engine and the other by the vehicle in motion (forexample, from the driven shaft). The pressure oil line 107extending-from the pump is connected to a pressure regulator R having aspring-loaded piston 215 and communicates with a selector valve W. Theselector valve W has a pilot valve member $93 therein operated by alever 199. The line Hi7 also communicates, through a branch line lid,with the pilot valve 1% of the output The lever 169 is moved to positionZ1 for forward gear position and to position Z2 for idling position.Other gear shift positions, for example, for revcrse and motor brake maybe provided.

Another line or conduit 111i connects the pump 1% with a speedcontroller V, consisting of a pilot valve 113 sliding in a cylinder 112and loaded by a spring 1.14. The spring 114 is influenced by a speedgovernor 115 which is driven by the vehicle, for example, from thedriven shaft of the transmission and thus, increases 3 or decreases thetension of the spring 114 as a function of the road speet. A return line111a extends from the body or cylinder 112 of the speed controller V tothe input side of the pump 106 so that the pressure in the chamber 116of the speed controller will be determined by the extent to which theend of line 11111 is covered by the pilot valve 113. As the valve 113moves downwardly, the line 1310 is progressively covered to decrease thereturn of hydraulic fluid to the inlet of the pump so that the pressurein chamber 116 increases up to the pressure developed at the output sideof pump "by lines 134, 135 and 136.

devices U1, U2, U3 and U4.

9 106. From the control chamber 116 containing the valve 113 of thespeed controller V a line 117 leads to a plurality of shifting devicesU1, U2, U3 and U4. respectively including pilot valves 118, 119, 120 and121. The line 117 opens into the upper portions 122, 123, 124 and 125 ofthe shifting devices U1, U2, U3 and U4, and through a branch line 126into the chamber 127 on the side of the pilot valve 113 opposite to thespring 114.

Branch lines 129, 131i, 131, 132 and 133 communicate with a line 128which is in communication with line 1437 throughthe selector valve 188when the latter is in forward gear position. The branch lines 129 and130 open into the upper and lower parts of the cylinder of device Uwhile the branch lines 131, 132 and 133 respectively open into the lowerportions of the cylinders of the devices U2, U3 and U4. The cylinders ofthe shifting devices are in communication with each other 7 A line 137leads from the pilot valve cylinder of the shifting device U1 to a shiftcylinder for the first gear, a line 138 from the device Uzto the shiftcylinder for the second gear, a line 139 from the device Us to the shiftcylinder for the third gear, a line 140 from the device U4 to the shiftcylinder for the fourth gear and a line 141 from the device U4 to theshift cylinder for the fifth gear.

The control chamber 142 of the controller L which receives the valve 105communicates through a line 143 with the left side of a piston 144 ofthe pilot valve 105 and through a line 1435, 1% opening into branchlines :147, 1455, 149, communicates with the lower pressure chambers 151to 154- of the pilot valves cylinders of the The pilot valves in thedevices U1, U2, U and U; are, as clearly shown in the drawing, formed asdifferential pistons, so that, if oil under pressure is admitted intothe central chambers 155 to 153, 21

pressure is built up which acts upon the pilot valves in downwarddirection.

Aline 159 branchesoif from the line 145 to communicate the outputcontroller L with a piston 16% of a pushrod control assembly D. Thisassembly includes, be-

sides piston ldil, further .pistons 161, 162, 163, 164, which havedifferent diameters, and are connected in series under the tension of aspring 165. A pushrrod 166cm the piston 161 is arranged in such a mannerthat itcomes within the range of the lower lever arm 167 of the poweroutput control member 131 when the piston 161 is in its left-hand endposition (as viewed in the drawing). The chamber 16% receiving thepiston 161 communicates through .a line 169 with the line 117 and hencewiththe control chamber 116 of the speed coni":

troller V. A line 1711 branching off from line 138 extendingto thesecond gear shifting device establishes communication with theright-hand side of the piston 164, and likewise a line 171 extends fromline 139 of the thirdgear shifting device to the piston 163, a line 172from ;line 140 of the fourth gear shifting device to the piston 162, anda line 173 from line 1 51 of the fifth gearto the piston 161.

The pilot valves 118 to 121 inclusive are urged downwardly by springs174 to 177 respectively, the springs being so proportioned that spring174 is the strongest and .177 the weakest. At the points designated by Othe lines and control chambers are open to the atmosphere.

The mode of operation of the described device is as follows: Each of thepilot valves 118, 119, 121i and 121 is subjected to a combined load fromabove exerted by the pressure dependent upon the speed of the drivenshaft of the transmission and controlled by the speed controller V, andby the related one of the springs 174 7 wards.

10 which, for example, correspond to the speed below 1 1, all of thepilot valves 118 to 121 are moved up by the selected poweroutput-dependent pressure which is efiective in the chambers 151 to 154through the lines 145, 146, 147, 148 and 149. If, in such a case, theselector valve W is in the position shown on the drawing, then the oilunder pressure from the pump 106 is passed through the selector valve,through line 129 and the control chamber containing the pilot valve 118,and into line 13-7 to engage the first gear. The lines 138 to 141 forthe second to fifith gear shifting cylinders are exposed to atmosphericpressure when the related pilot valves are raised. If the road speedincreases with constant power output setting, then the pressure, whichis effective upon the pilot valves from above, also increases in such amanner that this pressure at a certain road speed exceeds the pressurefrom below which is dependent upon the power output and moves therespective pilot valve down- Since the spring 174 is the strongest, thepilot valve 118 of the shifter device U1 is at first, at a definite roadspeed (1 12), moved downwards. (The automatic shiftgear is shown in thisposition on the drawing.) When .valve 113 is thus moved downwardly, line137 is opened to the atmosphere, while the pressure oil enters line 138119 and thus engages the second gear. Since the forced oil which hasentered the control chamber 155 (owing to the fact that the pilot valveis formed as a differentialpiston) exerts an additional downwardpressure upon the piston of valve 119, the pilot valve 119, after theshift, is held with increased force in its lower position, so that evenif the road speed should decrease again, the shift to low .gear takesplace only at a lower road speed than the shift to a higher gear.

The shift to the higher gears takes place in a manner corresponding tothe shift from first to second gear, and thatconforming to the speedsv23, 1 34 and v45 of Fig. 3.

When such a low power output is selected that the power dependentpressure even at low speeds of the driven .shaft or low road speeds, isinsufficient for the purpose of holding the pilot valves 118,119, 120and 121 in their upper positions, then, a higher gear is engaged atthese lower speeds. If, by way of example, at a definite speed.(forexample, vi) the selected power curve vlies below the output level V(Fig. 2), then all the pilot valves are 'in their lower position, Thiscauses the lines 137 to 149 to be opened to the atmosphere, whereas line141 via the selector valve W, lines 128 and 133 and chamber 158, isunder operating pressure. Accordingly, the fifth gear is engaged. If, atconstant road speed, the set power is increased by depressing the pedal101, which results in an additional tension of the spring 104andconcurrently an increase in pressure in the chamber 144, theninitially the pilot valve 121 is lifted since the spring 177 is weakest.This results in line 141 being opened to the atmosphere, while line 140is brought into communication with line 136, which in turn communicates,viacontrol chamber 157, with line 132 Thus, the fifth gear is disengagedand the fourth gear engaged. The point of passage from one gear totheother conforms in Fig. 2 to the intersection point of line 1 1 withcurve V. With further increase in poweron the perpendicular linefrompoint vrto point B1 of Fig. 2 at each respective crossing of thecurves IV, 111, H, the respective next following gear is successivelyengaged.

The mode of action of thepush-rod control device D, forminga part of theassembly of Fig. 4, is asfollows: The selectedpower-dependent pressureis eifective on the right-hand side of the piston through the line 159while the left hand side of the piston 161'is subjected to the force ofspring and also the speed-dependent pressure through the line 169. Thepistons 161 to 164 are graded to conform tothe gear shift positions. Ifthe drive, for example, with a selected power level N is in fifth gear(for example, at a driven shaft speed W) and henceforth the speed, at aconstant setting of the power, decreases, then the pressure acting inthe chamber 168 to the left of piston 161 drops so much, that at adefinite road speed (for example adjacent to 1/54) the force acting fromthe right, being composed of power-dependent pressure upon the piston160 and the force upon the piston 161 caused by the pressure oil flowingin line 173, predominates, so that the push-rod 166 is moved to the leftagainst the lever arm 167 of the power output control member 101 wherebya force is exerted upon the control member. Simultaneously thespeed-dependent pressure in line 117 has decreased so much that thepowerdependent pressure in the chamber 154 acting upon the pilot valve121 surmounts the counteracting pressure in the top chamber 125 andmoves the slide valve 121. up, thereby fifth gear is disengaged andfourth gear engaged. As an accompaniment to the disengagement of thefifth gear the pressure in the lines 141 and 173 drops, while lines 140,172 are put under pressure. piston 161, the piston 162 is subjected tothe pressure oil acting at the right-hand face thereof. However, sincethis piston is smaller than piston 161, the force applied by thepush-rod of the piston 62 is smaller and at first the speed-dependentpressure in the chamber 168 predominates again, so that the piston withthe push-rod 166 is moved again to the right. Not till the speed of thedriven side has decreased further (for example, to 1143) does thepressure upon the pistons 160 and 162 begin to surmount thecounterpressure in 'the chamber 168, effecting a repeat movement of thepush-rod toward the left and therewith exerting a repeat force upon thelever 101. At this instance shifting from fourth to third gear isactuated by the up movement of pilot valve 120.

In a similar manner, at the passage from third to econd and from secondto first gear, a force is exerted by the rod 166 upon the lever 101 byreason of the operating pressure becoming effective upon the piston 163and then on the piston 164.

Fig. 5 shows an arrangement for using the engine as a braking force. Thepreselector lever or the power output control member 201 is in thepresent instance connected through a link 202 with a lever 203 of apower output regulator, for example, that shown in Fig. 3, whereas lever206 which connects to an automatic gear shift, for example, the gearshift 7 of Fig. 3 which is shown in detail in Fig. 4-, is connected tothe link 202 by means of an intermediate transmission. This intermediatetransmission is formed by toothed segment 204 connected to link 202, apinion 205 meshing with the segment, and by a rod 207 which is attachedcrank-like to the pinion 205.

The power output control member 201 in the illustrated idling positionis supported against a movable stop 208 situated on a rod 209 which canbe actuated by the selector lever 210. The control lever 201 also has anextension 211 which serves as contact for an electric circuit in which asignal lamp 213 is connected so that as soon as the lever 211 touchesthe fixed contact 214, the circuit is closed and thus causes the lamp213 to be illuminated.

In the drawing the control lever 201 is shown in idling position. Inorder to change to greater power output the lever 201 is moved to theleft in the direction of the arrow y, to thereby rotate the pinionclockwise thus moving the crank rod 207 to the left. When applied to theautomatic gear shifting assembly of Fig. 4, this movement of rod 207causes the power-dependent pressure in chamber 142 to be correspondinglyincreased.

If it is desired to use the engine as a braking force, then the controllever 201 must be moved in the direction of the arrow y. However, thisis only possible if the control lever 210 is moved into position 210 toretract the stop 208. The pinion 205 is rotated by counter- Now insteadof clockwise movement of lever 201 in the direction y and this likewiseadjusts the automatic shiftgear on the linkage 206 for greater powerthrough the lever 206. However, at the same time the output regulator ofthe engine on the lever 203 is adjusted for lesser power and thereinlies the adaptability of the engine as a braking force.

Simultaneously with moving the lever 201 in direction y the contacts211, 214 are closed to cause the signal lamp to be illuminated.

The invention is not only applicable to carburetor engines but also inspirit and scope to other engines, for example diesel engines. In thislatter case instead of utilizing a throttle valve for control the amountof fuel to be injected, for example, delivered by a fuel injection pump,is controlled. In this case also a pressure below atmospheric could beused as the power-dependent value or factor with this low pressure beinginduced by a contraction or restricted neck corresponding to thecarburetor air venturi 10. It is to be understood that the invention isnot limited or restricted to the employment of such a pressure belowatmospheric as the powerdependent control value or factor, and thatother changes and modifications may be made in the described embodimentswithout departing from the scope or spirit of the invention as definedin the appended claims.

What is claimed is:

1. Apparatus for controlling an internal combustion engine driveassembly including a transmission having several gear ratios interposedbetween the engine and a driven shaft; said apparatus comprising feelermeans responsive to an operating characteristic of the engine whichvaries substantially proportionally to the power output of the engine,power output control means actuated by said feeler means formanipulating the engine throttle so that the power output tends to bemaintained at a preselected value, adjusting means operatively connectedto said feeler means for adjusting the latter to vary the preselectedvalue of power output which said control means tends to maintain, ashift device for shifting the transmission, means actuating said shiftdevice in response to changes of speed of the driven shaft ofpredetermined values, and means operatively connected to said adjustingmeans and to said shift device actuating means for adjusting saidpredetermined values of driven shaft speed in response to variations ofsaid preselected value of power output.

2. Apparatus according to claim 1; wherein said feeler means includes ananeroid, and means for subjecting said aneroid to the reduced pressureat the throat of the carburetor venturi associated with the engine; andwherein said power output control means is operatively connected to saidaneroid and is effective to move the engine throttle in a closingdirection when said reduced pressure at the throat of the carburetorventuri falls to a value indicating that the engine power output hasexceeded said preselected value thereof.

3. Apparatus according to claim 1; wherein said means operativelyconnected to said adjusting means and to said shift device actuatingmeans is effective to increase said predetermined values of driven shaftspeed simultaneously with the increasing of the preselected power outputby said adjusting means.

4. Apparatus according to claim 1; wherein said shift device comprises apilot valve for each gear ratio of the transmission, and meanscontrolled by each of said pilot valves for effecting the shift of thetransmission to the respective gear ratio; and wherein said meansactuating the shift device includes means urging each of said pilotvalves in one direction with a force proportional to the speed of thedriven shaft.

5. Apparatus according to claim 4; wherein said means operativelyconnected to said adjusting means and to said shift device actuatingmeans includes means urging each of said pilot valves in the oppositedirection with a 13 force proportional to the value of the selectedpoweroutput.

6. Apparatus according to claim 1; further comprising means actuatedby-said shift device and operative to displace said adjusting means inresponse to the operation of said shift device in-shifting thetransmission from a higher gear ratio to a lowergear'ratio.

7. A control device-for'a'drive assembly including an internalcombustion engine, a driven shaft and a multigear ratio transmissiontherebetween; said device comprising means for throttling the power ofthe engine, feeler means responsive to an operating characteristic ofthe engine which varies substantially proportionally to the power outputof the engine, said throttling means speeds of the driven shaft, andmeans operatively connected to said shifting device for increasing thevalues of said predetermined speeds in response to the increase of theselected power output by said adjusting means.

8. A control device according to claim 7; including resilient meansadjustably positioned in the path of movement of said adjusting means sothat the latter can be manipulated to set a power output value higherthan that defined by the position of said resilient means only byovercoming the yieldable resistance of the latter.

9. A control device for a drive assembly including an internalcombustion engine, a driven shaft and a multigear ratio transmissiontherebetween; said device comprising an air intake for the engine havinga restricted throat, a throttling element in said air intake, a conduitcommunicating with said restricted throat, a sealed housing connected tosaid conduit so that the pressure in said housing varies in response topressure changes at said restricted throat, an aneroid in said housing,control means operatively connected to said aneroid, adjusting meansconnected to said aneroid for varying the initial position of the latterand of said control means, actuating means for manipulating saidthrottling element in response to the position of said control means sothat a decrease of pressure at said throat below a predetermined value,as determined by the initial position of said aneroid, will result inclosing movement of said throttling element, a shift device for shiftingthe transmission in response to the attainment of predetermined speedsby the driven shaft, and means actuated by said adjusting means andoperatively connected to said shift device to increase saidpredetermined speeds of the driven shaft at which the transmission isshifted in response to movement of said adjusting means in the directionoperative to increase the pressure below atmospheric at said throat atwhich said throttling element begins said closing movement.

10. A control device for a drive assembly including an internalcombustion engine, a driven shaft and a multigear ratio transmissiontherebetween; said device comprising means for throttling the power ofthe engine, means controlling the operation of said throttling means inresponse to an operating characteristic of the engine which variessubstantially proportionally to the power output of the engine,adjusting means operatively connected to said controlling means forvarying the power at which the latter becomes effective to operate saidthrottling means, a shift device operative in response to predeterminedspeeds of the driven shaft to shift the transmission, and means actuatedby said adjusting means and operatively connected to said shift deviceto normally vary said predetermined speeds in accordance with variationsin the power at which said throttling means becomes effective, saidadjusting means in one position fit being operative to condition saidcontrolling means for maintaining said throttling means continuously ina power throttling position.

11.,A control device according to claim 10; wherein said means actuatedby said adjusting means and operatively connected to said' shift deviceincludes link means constructed and arranged to inversely vary saidpredetermined speeds with respect to the power at which said throttlingmeans becomes effective when said adjusting means is moved to said oneposition thereof.

12. An hydraulic control device for a drive assembly including aninternal combustion engine, a driven shaft and a multi-speedtransmission therebetween; said device comprising means for selecting adefinite engine power,

-' adevice =for'establishing an hydraulic pressure proportional to theselected engine power, a device for establishing an hydraulic pressureproportional to the speed of the driven shaft, pilot valves, gear shiftoperators, said pilot valves controlling the flow of fluid pressure tosaid gear shift operators, means for applying a load to each of saidpilot valves in one direction by said pressure proportional to the speedof the driven shaft and in the other direction by said pressureproportional to the selected power in such a manner that at constantselected power and increasing speed of the driven shaft said pilotvalves for the separate gear shift operators are successively moved insaid one direction into a position effecting the shift of the relatedspeed.

13. A control device according to claim 12 wherein said pilot valves areformed as differential pistons, means directing the hydraulic pressurewhich actuates the shifting against the differential area of each pistonas soon as the respective pilot valve has been moved into gear shiftingposition, thedifferential area of each piston being so arranged that thepressure brought to bear on said area acts in the same direction as saidpressure proportional to the speed of the driven shaft.

14. A control device according to claim 12 including, resilient elementswhich are effective upon said pilot valves in the same direction as saidpressure proportional to the speed of the driven shaft, the resilientelement which is associated with a lower gear shift position being ineach case stronger than the resilient element which is associated with ahigher gear shift position.

15. A control device according to claim 12 including, a control pistonfor each of the different gear shift positions, the related one of saidpistons being placed under hydraulic pressure when the respective gearis engaged, another piston, means for applying a pressure against thelatter proportional to the selected power, resilient means applying ayieldable force counteracting said pressures, means applying thepressure proportional to the speed of the driven shaft in a direction toalso counteract said aforementioned pressures, and means fortransmitting the movements of said pistons caused by the differences ofsaid pressures and said yieldable force to said means for selecting thepower of the engine in such a manner that said piston movements areperceptible in said selecting means.

16. A control device for a drive assembly including an internalcombustion engine, a driven shaft and a multigear ratio transmissiontherebetween; said control device comprising means for setting aselected power to be imparted to the driven shaft and for automaticallycontrolling the engine to maintain the power output substantiallyconstant at said selected power so that the performance of the engineremains substantially uniform at all speeds of the driven shaft, a shiftdevice for shifting the gear ratio of the transmission in response topredetermined speeds of the driven shaft, and means operativelyassociated with said shift device for varying said predetermined speedsin response to changes in said selected power set by the first mentionedmeans.

17. Control device according to claim 16 wherein said first mentionedmeans comprises an adjusting device for defining said selected power, athrottling member for controlling the power output of the engine, meansresponsive to the actual power output of the engine, and means formanipulating said throttling member by said adjusting device and thelast mentioned means in such a manner that said throttling member ismaintained in open position so long as the selected power is notattained, and is moved towards closed position as soon as said selectedpower is attained.

Hayes May 31, 1932 Bloxsom May 30, 1933 1 6 Erban Aug. 8, Fleischel Mar.5, Drabin Apr. 16, Vincent July 16, Livermore June 7, Brunner Oct. 31,Hale Dec. 16, Scott-Paine Sept. 28, Hefel Sept. 28, Lang et a1 June 27,Aspinwall Nov. 11, Britton Aug. 24, Peterson et al Nov. 23,

